| ( | 50 | + | m | ) | ( | 20 | − | 1 2 | m | ) | + | 100 | ( | 30 | + | 1 5 | m | ) | = | 50 | × | 80 | + | 30 | × | 100 | + | 250 |
| Left side of the equation = | 50 | ( | 20 | − | 1 2 | m | ) | + | m | ( | 20 | − | 1 2 | m | ) | + | 100 | ( | 30 | + | 1 5 | m | ) |
| = | 50 | × | 20 | − | 50 | × | 1 2 | m | + | m | ( | 20 | − | 1 2 | m | ) | + | 100 | ( | 30 | + | 1 5 | m | ) |
| = | 1000 | − | 25 | m | + | m | ( | 20 | − | 1 2 | m | ) | + | 100 | ( | 30 | + | 1 5 | m | ) |
| = | 1000 | − | 25 | m | + | m | × | 20 | − | m | × | 1 2 | m | + | 100 | ( | 30 | + | 1 5 | m | ) |
| = | 1000 | − | 5 | m | − | m | × | 1 2 | m | + | 100 | ( | 30 | + | 1 5 | m | ) |
| = | 1000 | − | 5 | m | − | m | × | 1 2 | m | + | 100 | × | 30 | + | 100 | × | 1 5 | m |
| = | 1000 | − | 5 | m | − | m | × | 1 2 | m | + | 3000 | + | 20 | m |
| = | 4000 | + | 15 | m | − | m | × | 1 2 | m |
| 4000 | + | 15 | m | − | m | × | 1 2 | m | = | 50 | × | 80 | + | 30 | × | 100 | + | 250 |
| Right side of the equation = | 4000 | + | 3000 | + | 250 |
| = | 7250 |
| 4000 | + | 15 | m | − | m | × | 1 2 | m | = | 7250 |